Can bath sink and utility sink drain into 1.5"...PHOTOS

Can I have a bath sink and a garage utility sink draining into a 1.5" drain?

Photo #2 is looking the opposite way as photo #1.

I'm rethinking my garage utility sink install. I posted a question about 2 weeks ago concerning that. Have another question. Attached are two photos of my main stack in basement. The 1.5" I have labeled in red is showing the drain for a 1st floor bath sink that eventually ties into the 2" before the stack.

In photo #2, the garage is on the other side of the wall to the left of photo.

In photo #1, can I connect the garage utility sink drain to the 1.5" that is horizontal right above the I-Beam(using a wye)?

Or do I have to extend the 2" a little and cut in a 2 x 2 x 1.5 wye where the run of the wye would pick up the existing bath sink and the tap of the wye would pick up the garage utility?

An inspector would want to see the laundry sink run with 2" until the vent and trap arm.

Click to expand...

I'm gonna have to look up sink, lav, laundry definitions and see how that compares with a slop sink for a garage. As a note the sink in garage will not be used for laundry....just a place to wash up instead of having to bend down to use spigots....see photo below. The two foam wrapped copper lines in photo #2 in post 1 are the hot/cold spigots in the photo below.

But if a garage sink has to be all 2" thats not a big deal.

Thanks again

Attached Files:

What you personally intend for the use of any given plumbing fixture is immaterial, in the eyes of Plumbing Correctness. The building,
and its plumbing system, will usually see a lengthy series of occupants, and highly varied use patterns.

someone went to a lot of trouble to post that, but in his case, it is more likely that he will use a "laundry tray" rather than a service sink, even though both require the same drainage according to the chart. Even if he uses a "kitchen sink" on a cabinet, the drain requirement would not change.

I was going by how we plumb on the West Coast.
And this is why West Coast plumbers laugh about the plumbing on the East Coast. I know when I visited my brother in Virginia, everything seemed undersized. Maybe that's why you guys get so good at running snake equipment.

West Coast plumbing is 1 DFU for 1.5" horizontal and 8 DFU for 2" horizontal
2 DFU for 1.5 vertical and 16 DFU for 2" vertical

someone went to a lot of trouble to post that, but in his case, it is more likely that he will use a "laundry tray" rather than a service sink, even though both require the same drainage according to the chart. Even if he uses a "kitchen sink" on a cabinet, the drain requirement would not change.

Click to expand...

You're correct hj... I am going to have a "laundry tray" sink in the garage...not necessarily a service sink. And as you say "laundry tray" sink and service sink are same dfu's

Here is a suggestion I received off site:

cut the 1-1/2 line to the lav out of the way and run 2 inch all the way towards the garage for the garage sink. Then pickup the lav drain with a 2x1-1/2x1-1/2 wye where it turns towards the foam in pic 2. That way I only have one line in that bay and would be much easier than trying to run another line next to the line that picks up the lav. I like this suggestion. Thanks Dan

Huh?
If the lav is on the way to the laundry tray, and 2" is being run there, then it's common to cut in a 2" x 1.5" combo or wye fitting for the lav as you pass by it.
2" x 2" x 1.5" combo.
End, end, side inlet

Huh?
If the lav is on the way to the laundry tray, and 2" is being run there, then it's common to cut in a 2" x 1.5" combo or wye fitting for the lav as you pass by it.
2" x 2" x 1.5" combo.
End, end, side inlet

Click to expand...

Yes Terry I think you said it better above.
I think the plan will be:

-cut out The majority of the existing 1.5" for the lav sink--highlighted in green in the photo below.
-the laundry sink for garage will come thru rim joist where the blue circle is in the photo--- between the two water lines which are wrapped in foam
-run all 2" to the laundry sink in the garage and the pick up the lav sink with a 2 x 2 x 1.5 wye.

That, or you may be able to wye off on the vertical too. Are the sinks above? Or straight out the wall?

I see from the previous post that they will revent at 42" above the floor before going out through the roof. Or if you use an AAV for the two of them, you can get an accessible box with grill if installing in-wall.
I prefer popping through the roof, but I don't know what you have above that.